1. Field
The described technology relates generally to a rechargeable battery that improves fastening force of a lead tab and an electrode terminal.
2. Description of the Related Art
A rechargeable battery includes an electrode assembly formed in a jelly roll shape by winding a positive electrode, a negative electrode, and a separator. The rechargeable battery further includes: positive and negative electrodes formed at both sides of the separator, a case housing the electrode assembly, a cap plate sealing an opening of the case, an electrode terminal electrically connected (coupled) to the electrode assembly and protruding to the outside of the cap plate through a terminal hole formed in the cap plate, and a lead tab, respectively connecting (coupling) the positive electrode and the negative electrode of the electrode assembly to the electrode terminal.
The lead tab is coupled (e.g. fastened) to the electrode terminal from an inner side of the cap plate by caulking and welding. The lead tab coupled to the electrode assembly is made of a thinner plate than the electrode terminal so that it has a weak supporting force, and accordingly, the lead tab may droop while being separated from the welded portion by slight vibration. That is, the lead tab may be bent at the welded portion.
When the drooping or bending of the lead tab becomes worse in the welded portion, the lead tab is separated from the electrode terminal at the welded portion so that the lead tab and the electrode terminal are electrically disconnected. Particularly, when the lead tab connected (coupled) to the negative electrode is made of copper, the lead tab is more easily drooped or bent at the welded portion with the electrode terminal so that the lead tab may be easily separated from the electrode terminal.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.